Process for finishing textiles made of fibers which contain keratin

ABSTRACT

A process for felt-proofing and dimensionally stabilizing textiles containing keratinous fibers with a single aqueous bath which contains both reducing agents and polyurethane polymers containing free isocyanate groups as well as polymers or copolymers based on vinyl or divinyl compounds. The aqueous bath has a pH of about 5.5 to about 6.5. The reducing agents used are salts or sulphurous acid or pyrosulphites. The free isocyanate groups of the polyurethane are bound to aliphatic carbon atoms.

United States Patent [:91

Schafer et al.

[ PROCESS FOR FINISHING TEXTILES MADE OF FIBERS WHICH CONTAIN KERATIN {75] Inventors: Karl Schafer, Opladen; Hans Schuster, Schildgen; Wolfgang Klebert, Leverkusen, all of Germany [73] Assignee: Bayer Aktiengesellschaft, Germany [22] Filed: Aug. 17, 1973 [21] Appl. No.: 389,300

[30] Foreign Application Priority Data Sept. 1, i972 Germany 2243068 [5|] Int. Cl. BOSD 3/02; BOSD 3/04 [58] Field Of Search ll7/l39.5 A, 14!, 16 KP,

ll7/l6l UH, l6l UF, ll9.8; 8/!28, l27.6; 427/377, 390; 428/425, 500, 538

[56] References Cited UNITED STATES PATENTS 3,049,445 8/1962 Lundgren et al. ll7/l4l Dec.9, 1975 3,423,166 1/1969 Peters et al. ll7/l4l X 3,498,740 3/l970 Cain 8/]276 3,529,990 9/l970 Becker et al l 17/1395 A 3,542,505 1 [/1970 Pittman et al. 8/l27.6 3,639,157 2/1972 Wunder et al. l|7/l39.5 A

Primary Examiner-Ralph Husack Assistant Examiner-Sadie L. Childs Attorney, Agent, or Firm-Lawrence S. Pope [57] ABSTRACT 6 Claims, N0 Drawings PROCESS FOR FINISHING TEXTILES MADE OF FIBERS WHICH CONTAIN KERATIN lt is known to use reducing agents for dimensionally stabilizing (surface-fixing) textiles made of fibers which contain keratin. Dimensional stability as used herein means the ability of a fabric to retain its shape and size after being worn, washed and dry cleaned. Felt-proofing means that no change in the Surface properties owing to shrinking and felting occurs when the textile is washed with the usual detergents.

The application of reaction products which contain free isocyanate groups in organic solvents or their application from aqueous baths which in addition contain polymers or copolymers based on vinyl or divinyl monomers for felt-proofing textiles which contain keratin fibers is also known (U.S. Pat. No. 3,639,157).

Two-stage processes for finishing fibrous material which contains keratin to render it felt-proof and di-- mensionally stable have also been disclosed in US. Pat. No. 3,498,740 and in German Offenlegungsschrift No. 1,906,514. In these processes, the textile is either treated with a reducing agent in the first stage of the process and thereafter a synthetic resin, e.g., a reaction product of polyols and polyisocyanates which contains free isocyanate groups, dissolved in an organic solvent is applied in the second stage or conversely.

These two-stage processes are complicated and expensive to carry out. Moreover, some textiles which contain keratin fibers, such as loose-textured fabrics, especially knitted goods such as double jersey or felts such as clothing or inter-lining felts or interfacings, cannot be sufficiently stabilized in their surface dimensions by these known processes.

It is an object of this invention to provide a simple and economic process by which textiles made of fibers which contain keratin can be permanently felt-proofed and dimensionally stabilized.

It has now surprisingly been found that the application of a single aqueous bath which contains both reducing agents and reaction products of polyols and polyisocyanates which contain free isocyanate groups and polymers or copolymers based on vinyl or divinyl compounds provide an excellent felt-free finish and dimensional stability even in the textile materials mentioned above if a. the reducing agents are salts of sulphurous acid or pyrosulphites,

b. the aqueous bath has a pH of about 5.5 to 6.5, and

c. the free isocyanate groups are aliphatically bound.

This invention therefore relates to a process for the dimensional stabilization and felt-proofing of textiles made of fibers which contain keratin, in which the textile is treated with an aqueous bath at a pH of about 5.5 to 6.5 which contains salts of sulphurous acid or pyrosulphites as reducing agents, a dispersion of a reaction product which contains aliphatically bound free isocyanate groups and a dispersion of a polymer or copolymer based on vinyl or divinyl monomers.

The following are examples of suitable salts of sulphurous acid or pyrosulphites useful as reducing agents: alkali metal salts such as sodium sulphite, sodium pyrosulphite, potassium sulphite or potassium pyrosulphite, ammonium sulphite, hydrazine sulphite or methyl hydrazine sulphite, sulphurous acid salts of aliphatic amines such as ethylamine, propylamine, ethylenediamine, N,N,N', N'-tetramethyl-ethylenediamine, triethylenediamine, permethyl diethylenediamtions, are obtained only if the solutions are buffered with ammonia or the above-mentioned amines so that the baths according to the invention have a pH of about 6. Any excess of ammonia or amine must be avoided because the free isocyanate groups readily react with ammonia, amines or other compounds which contain active hydrogen atoms so that the baths then become unusable for the process according to the invention. lf sodium sulphite is used, the bath should preferably be buffered with acetic acid.

The compounds used according to the invention which contain free isocyanate groups are reaction products of organic polyisocyanates, preferably aliphatic or cycloaliphatic diisocyanates, with organic polyhydroxyl compounds with a molecular weight of 500-6000, preferably 800-3500, which contain at least two hydroxyl groups.

The polyhydroxyl compounds used may be polyethers, for example polyethylene glycol, polypropylene glycol, polybutylene glycol or polyhexylene glycol. or polyesters of aliphatic dicarboxylic acids such as succinic acid, adipic acid, sebacic acid or maleic acid and polyalcohols such as ethylene glycol, diethylene glycol, propylene glycol. butane-diol or neopentyl glycol.

The following are given as examples of suitable polyisocyanates: hexamethylene diisocyanate, tetramethylene diisocyanate, cyclohexane-l,4-diisocyanate, dicyclohexylmethane-4,4'-diisocyanate, hexahydrotolylene-2,4- and -2,6-diisocyanate, and triisocyanates, e.g., the compounds of the formula obtained from 3 mols of hexamethylene diisocyanate and l mol of water.

The reaction products of polyols and polyisocyanates containing free isocyanate groups which are used in the process according to the invention are prepared by reacting an excess of the polyisocyanate with the polyol, as shown below in Example A and e.g., as described in US. Pat. No. 3,639,157.

The polyisocyanates used for the process according to the invention may also be polyisocyanates of the general formula A[ -o-co-(O).. R-NCO],,. in which m represents an integer of from 2 to ID and n represents 0 or I. A represents an m valent group with a molecular weight of from 500-|8,000 whichislree from Zerewitinow active hydrogen atoms and which is formed by the removal of the hydroxyl groups from high-molecular weight polyhydroxyl compounds, and

R represents a divalent aliphatic or cycloaliphatic hydrocarbon group which contains from I 20 carbon atoms.

These polyisocyanates may be prepared by the process described in copending US. Ser. No. 244,220.

Aromatic polyisocyanates are generally not suitable for the process according to the invention because the polyaddition products with free NCO-groups prepared from them are liable to react with the water in the aqueous bath and to be discolored and degraded by light.

The polymers or copolymers used according to the invention are synthesized from monomers such as ethylene, propylene, vinyl chloride, vinyl acetate, vinyl ethers, styrene or divinyl benzene, butadiene, isoprene or chloroprene and a, B-unsaturated carboxylic acids such as acrylic acid or methacrylic acid or their esters, amides or nitriles.

Polymers which contain groups capable of reacting with isocyanates are particularly suitable. Among these may be included e.g., the polymers obtained from acrylic acid, methacrylic acid, their hydroxyalkyl esters or amides and the copolymers obtained when Nmethylolacrylamide, N-methylolmethacrylamide or derivatives of these two compounds obtained by reacting them with alcohols which contain at least one other functional group are copolymerized with other olefinically unsaturated compounds, e.g., by the process according to US. Pat. No. 3,243,399.

To prepare the finishing baths according to the invention, the reaction products which contain free isocyanate groups are emulsified in water with the aid of a non-ionogenic or anion-active emulsifier as exemplified in Example A, using a high-speed stirrer. The above-mentioned polymers or copolymers based on vinyl compounds are added to the emulsion. The resulting polymer dispersion preferably has a solids content of about 40%. The dispersion is then diluted with water 'to the extent required to obtain the desired final volume after the addition of the aqueous solutions of the salts of sulphurous acid.

When adding these sulphite solutions, it is necessary to insure that the pH is adjusted to about 5.5 6.5, i.e. about 6.

The reaction products which contain free isocyanate groups are added to the aqueous baths in quantities of -200 g per liter, preferably 40-60 g per liter. The quantity of the above-mentioned polymers or copolymers based on vinyl compounds is 5- 100g, preferably g. The aqueous bath contains about 10- 100 g of reducing agent per liter, preferably 20- 50 g per 1iter.

The textile is dipped into the bath and the excess liquid is then removed by squeezing or spinning. Alternatively, the baths according to the invention may be sprayed on the textile. The textile is then dried at 90- 10C for 5- 10 minutes and treated with steam for 3- 5 minutes.

After the steam treatment, the textile is preferably washed with l- 2 g per liter of a commercial non-ionogenic or anion-active surface-active agent at C for 10- 15 minutes.

Textiles which have been treated according to the invention can be dyed and printed and are not felted by the dyeing process.

The treatment according to the invention, may of course, also be applied to textiles which contain other fibers in addition to keratin fibers, e.g. synthetic fibers or cellulose fibers.

The following examples illustrate the excellent surface stabilizing effect obtained by the process according to the invention and the freedom from felting imparted to textiles which contain keratin fibers.

EXAMPLE A A pure wool clothing felt (200 g per square meter) is treated with aqueous baths containing the following substances per liter:

EXPERIMENT 1 g of an aqueous emulsion of the NCO prepolymer described below; 20 g of a 40% aqueous dispersion of the copolymers described below.

3000 g of a polypropylene glycol which has been prepared by propoxylation of trimethylolpropane and which has an OH-number of 55.5 and a molecular weight of 3000 is heated to C with 535 g of hexamethylene diisocyanate for 2 hours and then to C for 1 hours.

An emulsion is prepared from 40 g of the resulting reaction product which contains 3.9 percent by weight of free isocyanate groups, 10 g of ethyl acetate and 40 g of water with the addition of l g of a paraffin sulphonate, using a high-speed stirrer. A 40% aqueous dispersion of the copolymer of 80 parts of butyl acrylate, 10 parts of styrene and 10 parts of acrylamide is added to the resulting emulsion and made up to 1 litre with water.

EXPERIMENT 2 The same reaction mixture as in experiment 1. Addition of 100 g of a 40% aqueous sodium bisulphite solution.

EXPERIMENT 3 The same reaction mixture as in experiment 1. Addition of 200 g of a mixture of 500 g of sodium bisulphite solution (40%),

95 g of ammonia solution (25% and 405 g of water.

EXPERIMENT 4 The same reaction mixture as in experiment 1. Addition of 50 g of sodium sulphite dissolved in g of water and 5 g of glacial acetic acid.

EXPERIMENT 5 The same reaction mixture as in experiment 1. Addition of 200 g of a mixture of 56 g of triethylenediamine,

260 g of sodium bisulphite solution (40%),

124 g of water and 60 g of acetic acid.

EXPERIMENT 6 The same reaction mixture as in experiment I. Addition of 200 g of a mixture of 116 g of tetramethyl ethylenediamine,

520 g of sodium bisulphite solution (40%) and 364 g of water.

EXPERIMENT 7 The same reaction mixture as in experiment 1. Addition of 200 g of a mixture of 58 g of permethyl diethylenetriamine,

260 g of sodium bisulphite solution (40%),

122 g of water and 60 g of acetic acid.

Various samples of the pure wool clothing felt mentioned above are dipped into the baths prepared in ex periments l to 7 and then squeezed off to reduce the uptake of liquor to 100%.

The samples are then dried at 100C and treated with steam at 100C for 3 minutes. After the steam treatment, the samples are washed with 1% solution of the sodium salt of a paraffin sulphonate at 40C for minutes and dried.

The clothing felt treated according to the invention was stored at room temperature for 3 days and then tested for surface stability and freedom from felting by treating it in a Cubex apparatus for 60 minutes, using a bath ratio of l 15.

The following table indicates the excellent surface stability and freedom from felting of textile material treated according to the invention.

% Surface shrinkage Remark appearance of fabric Experiments 3-7 were repeated in experiments 8l2 but without the addition of a reaction product which contains free isocyanate groups.

The results are shown in the following table.

1: Surface Shrinkage Experiment due to felting Remark 8 33.6 completely felted 9 30.5 10 36.3 l 1 36.4 12 35.6

It is clear that a dimensionally stable textile is not obtained without using a reaction product which contains free isocyanate groups.

EXAMPLE B An interlining made of pure wool (l 10 g per square meter) is treated with aqueous baths which contain the following substances per liter:

EXPERIMENT l 100 g of the emulsion of a reaction product containing free isocyanate groups described in example A;

g of the aqueous dispersion of a copolymer described in example A.

EXPERIMENT 2 The same reaction mixture as in experiment 1 but with the addition of 150 g of a mixture of 500 g of sodium bisulphite solution (40%),

95 g of ammonia solution and 405 g of water.

Preparation of the bath and its application are carried out in the manner described in example A. The following table shows the effectiveness of the treatment according to the invention on the woolen interlining (tested on a Cubex apparatus for minutes, using a bath ratio of l 15).

% Surface shrinkage Remark completely felted moderately felled smooth, clear appearance of the fabric Untreated textile: Experiment 1: Experiment 2:

(textile treated according to the invention) EXAMPLE C(EXPERIMENT CARRIED OUT FOR COMPARISON) EXPERIMENT 1 (SINGLE BATH) g of the emulsion of reaction product which contains free isocyanate groups described in example A;

20 g of the dispersion of copolymers described in Example A;

200 g of the solution of sodium bisulphite and tetramethyl ethylenediamine described in example A, experiment 6. Preparation and application of the bath are carried out as in example A.

EX PERlM ENT 2(TWO-STAGE) In the first stage, the clothing felt mentioned above is treated with an aqueous bath which contains 200 g per liter of the solution of sodium bisulphite and tetramethyl ethylenediamine described in example A, experiment 6, as well as l g of the sodium salt of a paraffin sulphonate.

The treatment is carried out by immersing the clothing felt into the bath and then squeezing off excess liquor to reduce the liquor uptake to 100%. The felt is dried at 100C and treated with steam at 100C for 3 minutes.

In the second stage, the felt is treated with an aqueous bath which contains 100 g per liter of the emulsion of a reaction product with free isocyanate groups described in example A and 20 g per liter of the dispersion of a copolymer described in example A.

The treatment is carried out by immersing the felt in the bath and then squeezing it off to reduce the liquor uptake to 100% and drying it for 15 minutes at 100C. The felt is then stored at room temperature for 12 hours, washed with l g per liter of the sodium salt of a paraffin sulphonate at 40C for 10 minutes and then dried.

EXPERIMENT 3 (TWO-STAGE) [n the first stage, the clothing felt mentioned above is treated with an aqueous bath which contains 100 g per liter of the emulsion of a reaction product with free isocyanate groups described in example A and 200 g per liter of the dispersion of a copolymer described in example A.

The treatment is carried out by immersing the clothing felt in the bath and then squeezing off the excess liquor to reduce the liquor uptake to 100%. The felt is then dried at 100C for 15 minutes.

In the second stage, the felt is treated with an aqueous bath which contains 200 g per liter of the solution of sodium bisulphite and tetramethyl ethylenediamine described in example A and l g of the sodium salt ofa paraffin sulphonate.

The felt is then dried at 100C for 3 minutes and treated with steam at 100C.

After the treatment, the textile was stored at room temperature for l2 hours, washed with l g per liter of the sodium salt of a paraffin sulphonate and dried.

The dimensional stability and freedom from felting were tested in a Cubex apparatus using a bath ratio of l:l5 for 60 minutes.

The following table shows the particularly advantageous finishing effects obtained by applying the singlebath treatment according to the invention to the clothing felt.

A fabric consisting of 70 wool and 30 polyester fibres 160 g per square meter) is treated with an aqueous bath containing the following substances per litre:

I g of an aqueous emulsion of the NCO prepolymer described below;

30 g of a 40 aqueous dispersion of the copolymer described in Example A;

50 g of sodium bisulphite, dissolved in a mixture of 145 g of water and g of acetic acid.

The fabric is dipped into the bath and then squeezed off to reduce the uptake of liquor to about I00 The sample is then dried for minutes at 100C and treated with steam at 100C for 3 minutes. After the steam treatment the sample is washed with a l solution of the sodium salt of a paraffin sulphonate at 40C for l0 minutes and dried.

Preparation of the prepolymer:

35l g of 6-isocyanato caproyl chloride are added slowly with stirring at C to a mixture comprising 2000 g of a polyether from 1,1 ,l-trimethylol propane and propylene oxide (OH number 56) and 230 g of triethyl amine. The reacting mixture is stirred for 8 hours at room temperature. Then the triethyl ammonium chloride which has precipitated is filtered off, the reaction product being obtained in form of a slightly yellow, low viscous liquid in yield.

An emulsion is prepared from g of the above prepolymer, 10 g of ethyl acetate and 90 g of water with the addition of l g of the sodium salt of a paraffin sulphonic acid, using a high speed stirrer. A 40 aqueous dispersion of the copolymer described in Example A is added to the resulting emulsion and the mixture made up to 1 litre with water.

The following table indicates the excellent improvement of surface stability and freedom from felting of textile material achieved by treatment according to the invention:

% Surface shrinkage A fabric made of 50 wool and 50 cotton fibres was treated according to Example D.

% Surface shrinkage due to felting Remark Untreated textile 8,9 felted Textile treated according to 2,6 smooth, clear appeathe invention rance of fabric What is claimed is: l. A process for imparting dimensional stability and felt proofing to textiles containing at least some keratinous fibers which comprises treating said textiles with an aqueous bath which contains:

a. salts of sulphurous acid or pyrosulphites as reducing agents,

b. a polyurethane which contains free isocyanate groups prepared by a process which comprises reacting excess of an aliphatic or cycloaliphatic diisocyanate with organic polyhydroxyl compounds and which is emulsified to form an aqueous emulsion with the aid of an non-iogenic or an ion active emulsifier using a high speed stirrer, and

c. a dispersion of a polymer or copolymer based on vinyl monomers or divinyl monomers which is formed by adding the polymer or copolymer to said polyurethane dispersion,

said aqueous bath having a pH of about 5.5 to about 6.5, drying the treated textile at a temperature of 90 to l00C and then treating it with steam at about 100C.

2. The process of claim 1 wherein said reducing agents are salts of sulphurous acid with alkali metals, ammonia, hydrazine, methyl hydrazine or an aliphatic amine.

3. The process of claim 1 wherein said reducing agents are buffered so that the aqueous bath has a pH of about 6.

4. The process of claim 1 wherein said polyurethane has a molecular weight of about 500 to about 6000.

5. in a process for imparting dimensional stability and felt-proofing to textiles containing at least some keratinous fibers by treating said textiles with aqueous baths, drying the textile and treating the textile with steam, the improvement wherein the textile is treated with a single aqueous bath which contains:

a. salts of sulphurous acid or pyrosulphites as reducing agents,

b. a polyurethane which contains free isocyanate groups prepared by a process which comprises reacting excess of an aliphatic or cycloaliphatic diisocyanate with an organic polyhydroxyl compound, and

c. a dispersion of a polymer or copolymer based on vinyl monomers or divinyl monomers,

said aqueous bath having a pH of about 5.5 to about 6.5.

6. In a process for imparting dimensional stability and felt proofing to textiles containing at least some kerati- 10 nous fibers by treating said textiles with aqueous baths, drying the textiles at a temperature of to C, and treating the textile with steam at about 100C. the improvement wherein the textile is treated with a single aqueous bath which contains:

a. salts of sulphurous acid or pyrosulphites as reducing agents,

b. a polyurethane which contains free isocyanate groups prepared by a process which comprises reacting excess of an aliphatic or cycloaliphatic diisocyanate with an organic polyhydroxyl compound, and

c. a dispersion of a polymer or copolymer based on vinyl monomers or divinyl monomers,

said aqueous bath having a pH of about 55 to 6.5

* I i l 

1. A PROCESS FOR IMPARTING DIMENSIONAL STABILITY AND FELT PROOFING TO TEXTILES CONTAINING AT LEAST SOME KERATINOUS FIBERS WHICH COMPRISES TREATING SAID TEXTILES WITH AN AQUEOUS BATH WHICH CONTAINS: A. SALTS OF SULPHUROUS ACID OR PYROSULPHITES AS REDUCING AGENTS, B. A POLYURETHANE WHICH CONTAINS FREE ISOCYANATE GROUPS PREPARED BY A PROCESS WHICH COMPRISES REACTING EXCESS OF AN ALIPHATIC OR CYCLOALIPHATIC DIISOCYANATE WITH ORGANIC POLYHYDROXYL COMPOUNDS AND WHICH IS EMULSIFIED TO FORM AN AQUEOUS EMULSION WITH THE AID OF AN NON-IOGENIC OR AN ION ACTIVE EMULSIFIER USING A HIGH SPEED STIRRER, AND C. A DISPERSION OF A POLYMER OR COPOLYMER BASED ON VINYL MONOMERS OR DIVINYL MONOMERS WHICH IS FORMED BY ADDING THE POLYMER OR COPOLYMER TO SAID POLYURETHANE DISPERSION, SAID AQUEOUS BATH HAVING A PH OF ABOUT 5.5 TO ABOUT 6.5, DRYING THE TREATED TEXTILE AT A TEMPERATURE OF 90* TO 100*C AND THEN TREATING IT WITH STEAM AT ABOUT 100*C.
 2. The process of claim 1 wherein said reducing agents are salts of sulphurous acid with alkali metals, ammonia, hydrazine, methyl hydrazine or an aliphatic amine.
 3. The process of claim 1 wherein said reducing agents are buffered so that the aqueous bath has a pH of about
 6. 4. The process of claim 1 wherein said polyurethane has a molecular weight of about 500 to about
 6000. 5. In a process for imparting dimensional stability and felt-proofing to textiles containing at least some keratinous fibers by treating said textiles with aqueous baths, drying the textile and treating the textile with steam, the improvement wherein the textile is treated with a single aqueous bath which contains: a. salts of sulphurous acid or pyrosulphites as reducing agents, b. a polyurethane which contains free isocyanate groups prepared by a process which comprises reacting excess of an aliphatic or cycloaliphatic diisocyanate with an organic polyhydroxyl compound, and c. a dispersion of a polymer or copolymer based on vinyl monomers or divinyl monomers, said aqueous bath having a pH of about 5.5 to about 6.5.
 6. In a process for imparting dimensional stability and felt proofing to textiles containing at least some keratinous fibers by treating said textiles with aqueous baths, drying the textiles at a temperature of 90* to 100*C., and treating the textile with steam at about 100*C. the improvement wherein the textile is treated with a single aqueous bath which contains: a. salts of sulphurous acid or pyrosulphites as reducing agents, b. a polyurethane which contains free isocyanate groups prepared by a process which comprises reacting excess of an aliphatic or cycloaliphatic diisocyanate with an organic polyhydroxyl compound, and c. a dispersion of a polymer or copolymer based on vinyl monomers or divinyl monomers, said aqueous bath having a pH of about 5.5 to 6.5 